Cyclonic separator assembly for a vacuum cleaner

ABSTRACT

A cyclonic separator assembly for use with a vacuum cleaner includes a body having an inlet, an outlet, and an inner surface. The cyclonic separator assembly also includes a cyclone unit positioned within the body between the inlet and the outlet. The cyclone unit has an outer perimeter that is spaced apart from the inner surface of the body to define an inlet space therebetween. The cyclone unit includes a plurality of first cyclones in communication with the inlet space and arranged along an outer circle adjacent the outer perimeter. The cyclone unit also includes a plurality of second cyclones in communication with the inlet space and arranged along an inner circle that is spaced apart from the outer circle such that each second cyclone is nested between two adjacent first cyclones. The plurality of first cyclones and the plurality of second cyclones are arranged in parallel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/176,266, filed Feb. 10, 2014, which is a divisional application ofU.S. patent application Ser. No. 13/764,311, now U.S. Pat. No.8,679,211, the entire contents all of which are hereby incorporated byreference herein.

FIELD OF THE INVENTION

The present invention relates to vacuum cleaners and, more particularly,to cyclonic separator assemblies for vacuum cleaners.

SUMMARY

In one embodiment, the invention provides a cyclonic separator assemblyfor use with a vacuum cleaner. The cyclonic separator assembly includesa body having an inlet, an outlet, and an inner surface. The cyclonicseparator assembly also includes a cyclone unit positioned within thebody between the inlet and the outlet. The cyclone unit has an outerperimeter that is spaced apart from the inner surface of the body todefine an inlet space therebetween. The cyclone unit includes aplurality of first cyclones in communication with the inlet space. Theplurality of first cyclones is arranged along an outer circle adjacentthe outer perimeter. The cyclone unit also includes a plurality ofsecond cyclones in communication with the inlet space. The plurality ofsecond cyclones is arranged along an inner circle that is spaced apartfrom the outer circle such that each second cyclone is nested betweentwo adjacent first cyclones. The plurality of first cyclones and theplurality of second cyclones are arranged in parallel.

In another embodiment, the invention provides a cyclonic separatorassembly for use with a vacuum cleaner. The cyclonic separator assemblyincludes a body having an inlet and an outlet. The cyclonic separatorassembly also includes a cyclone unit positioned within the body betweenthe inlet and the outlet. The cyclone unit has an outer perimeter. Thecyclone unit includes a plurality of first cyclones arranged along anouter circle adjacent the outer perimeter, and a plurality of secondcyclones arranged along an inner circle that is spaced apart from theouter circle. The plurality of first cyclones and the plurality ofsecond cyclones are arranged in parallel. The number of cyclones in theplurality of first cyclones is substantially equal to the number ofcyclones in the plurality of second cyclones.

In yet another embodiment, the invention provides a cyclonic separatorassembly for use with a vacuum cleaner. The cyclonic separator assemblyincludes a body having an inlet, an outlet, and an inner surface. Thecyclonic separator also includes a cyclone unit positioned within thebody between the inlet and the outlet. The cyclone unit has an outerperimeter that is spaced apart from the inner surface of the body todefine an inlet space therebetween. The cyclone unit includes aplurality of first cyclones arranged along an outer circle adjacent theouter perimeter, and a plurality of first inlet paths extending from theinlet space to the plurality of first cyclones. Each first inlet pathhas a first length. The cyclone unit also includes a plurality of secondcyclones arranged along an inner circle that is spaced apart from theouter circle, and a plurality of second inlet paths extending from theinlet space to the plurality of second cyclones. Each second inlet pathhas a second length. A ratio of the second length to the first length isless than 2.

In still another embodiment, the invention provides a cyclonic separatorassembly for use with a vacuum cleaner. The cyclonic separator assemblyincludes a body having an inlet, an outlet, and a central longitudinalaxis. The cyclonic separator assembly also includes a cyclone unitpositioned within the body between the inlet and the outlet. The cycloneunit has an outer perimeter that defines a total cross-sectional area ofthe cyclone unit measured perpendicular to the central longitudinalaxis. The cyclone unit includes a plurality of first cyclones arrangedalong an outer circle adjacent the outer perimeter. Each first cyclonehas an air outlet, a particle outlet, a first longitudinal axisextending between the air outlet and the particle outlet, and a firstcross-sectional area measured perpendicular to the first longitudinalaxis. The cyclone unit also includes a plurality of second cyclonesarranged along an inner circle that is spaced apart from the outercircle. Each second cyclone has an air outlet, a particle outlet, asecond longitudinal axis extending between the air outlet and theparticle outlet, and a second cross-sectional area measuredperpendicular to the second longitudinal axis. The plurality of firstcyclones and the plurality of second cyclones are arranged in parallel.A ratio of the sum of the first and second cross-sectional areas to thetotal cross-sectional area is between about 0.4 and about 0.6.

In yet still another embodiment, the invention provides a cyclonicseparator assembly for use with a vacuum cleaner. The cyclonic separatorassembly includes a body having an inlet, an outlet, and an innersurface. The cyclonic separator assembly also includes a cyclone unitpositioned within the body between the inlet and the outlet. The cycloneunit has an outer perimeter that is spaced apart from the inner surfaceof the body to define an inlet space therebetween. The cyclone unitincludes a plurality of first cyclones arranged along an outer circleadjacent the outer perimeter, and a plurality of first inlet pathsextending from the inlet space to the plurality of first cyclones. Eachfirst inlet path has an end at the outer perimeter of the cyclone unit.The ends of the plurality of first inlet paths are circumferentiallyspaced evenly about the outer perimeter. The cyclone unit also includesa plurality of second cyclones arranged along an inner circle that isspaced apart from the outer circle, and a plurality of second inletpaths extending from the inlet space to the plurality of secondcyclones. Each second inlet path has an end at the outer perimeter ofthe cyclone unit. The ends of the plurality of second inlet paths arecircumferentially spaced evenly about the outer perimeter.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vacuum cleaner.

FIG. 2 is an exploded perspective view of a cyclonic separator assemblyof the vacuum cleaner.

FIG. 3 is a top view of a cyclone unit positioned within the cyclonicseparator assembly.

FIG. 4 is a cross-sectional view of the cyclonic separator assemblytaken along section line 4-4 of FIG. 3.

FIG. 5 is a cross-sectional view of the cyclonic separator assemblytaken along section line 5-5 of FIG. 3.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways.

FIG. 1 illustrates a vacuum cleaner 10 for vacuuming a surface. In theillustrated embodiment, the vacuum cleaner 10 is an upright-style vacuumcleaner that includes a foot 14 and a handle 18 pivotally coupled to thefoot 14. In other embodiments, the vacuum cleaner 10 may be acanister-style vacuum. The illustrated vacuum cleaner 10 includes acyclonic separator assembly 22 to separate dirt, dust, and other debrisfrom an airflow drawn in through a nozzle in the foot 14 or an accessorytool. The cyclonic separator assembly 22 is removably mounted on thefoot 14 and the handle 18 to facilitate emptying assembly 22 when full.

As shown in FIG. 2, the cyclonic separator assembly 22 includes a body26, an inner dirt cup 30, a cyclone unit 34, and a cover 38. The body 26defines a primary cyclone stage of the cyclonic separator assembly 22.The cyclone unit 34 defines a secondary cyclone stage of the cyclonicseparator assembly 22. The primary and secondary cyclone stages arearranged in series such that an airflow entering the assembly 22 firsttravels through the primary cyclone stage and then travels through thesecondary cyclone stage. The primary cyclone stage separates relativelylarge particles from the airflow, while the secondary cyclone stageseparates relatively small particles from the airflow before the airflowis discharged back into the environment.

In the illustrated embodiment, the body 30 is divided into a lower bodyportion 42, a mid body portion 46, and an upper body portion 50. Whenassembled together, the body portions 42, 46, 50 define an outer surface54 (FIG. 1) of the assembly 22 and a central longitudinal axis 58 (FIGS.4 and 5). The lower body portion 42 includes an inlet 62 that receivesairflow from the nozzle in the foot 14 or the accessory tool. A primarydirt cup 66 is defined by the lower body 42 between an inner surface 70of the lower body 42 and an outer surface 74 of the inner dirt cup 30.The primary dirt cup 66 collects particles that fall out of the airflowas the airflow travels through the primary cyclone stage. The mid bodyportion 46 is mounted on top of the lower body portion 42 and includes aperforated baffle 78 that extends into the lower body portion 42. Theupper body portion 50 is mounted on top of the mid body portion 46 andthe cyclone unit 34. The upper body portion 50 includes a plurality ofinlet tubes 82 (FIG. 4) and an outlet 86. The inlet tubes 82 communicatewith the cyclone unit 34 to receive the airflow from the cyclone unit34. The outlet 86 directs the airflow out of the assembly 22.

As shown in FIGS. 4 and 5, the inner dirt cup 30 is positioned withinthe lower body portion 42 beneath the cyclone unit 34. The inner, orsecondary, dirt cup 30 collects particles that fall out of the airflowas the airflow travels through the secondary cyclone stage. In theillustrated embodiment, the inner dirt cup 30 is centrally locatedwithin the body 26 (e.g., axially aligned with the central longitudinalaxis 58). In other embodiments, the inner dirt cup 30 may be positionedelsewhere relative to the body 26.

The cyclone unit 34 is positioned within the mid body portion 46 andmounted on top of the inner dirt cup 30. The cyclone unit 34 includes aplurality of first cyclones 90 and a plurality of second cyclones 94that are arranged in parallel to receive airflow from the primarycyclone stage. In the illustrated embodiment, the first and secondcyclones 90, 94 are integrally formed (e.g., molded) as a single unitsuch that the cyclone unit 34 is a single, unitary body. In otherembodiments, the first and second cyclones 90, 94 may be discretecomponents that are coupled together to form the cyclone unit 34. Thecyclone unit 34 has an outer perimeter 98 that is spaced apart from aninner surface 102 of the mid body portion 46. The cyclone unit 34 andthe mid body portion 46 thereby define an inlet space or gap 106 thatreceives airflow from the first cyclone stage (i.e., the lower bodyportion 42) and supplies the airflow to the second cyclone stage (i.e.,the cyclone unit 34).

All of the illustrated cyclones 90, 94 are generally the same shape andsize. The cyclones 90, 94 are tapered tubes that extend from an uppersurface 110 of the cyclone unit 34 toward the inner dirt cup 30. Eachcyclone 90, 94 includes an inlet 114, an air outlet 118, and a particleoutlet 122. The inlets 114 communicate with inlet paths 126, 130 formedon the upper surface 110 of the cyclone unit 34. Each inlet path 126,130 extends between the inlet space 106 and the inlet 114 of thecorresponding cyclone 90, 94 to direct airflow from the inlet space 106into the cyclone 90, 94. In the illustrated embodiment, each inlet path126, 130 is associated with one cyclone 90, 94. In other embodiments,one inlet path 126, 130 may be associated with two or more cyclones 90,94. The first inlet paths 126, which extend between the inlet space 106and the first cyclones 90, are generally shorter than the second inletpaths 130, which extend between the inlet space 106 and the secondcyclones 94. The first inlet paths 126 each have a first length L₁, andthe second inlet paths 130 each have a second length L₂. The length L₁,L₂ of each inlet path 126, 130 is measured along a center of the inletpath 126, 130 from the outer perimeter 98 of cyclone unit 34 to theinlet 114 of the corresponding cyclone 90, 94. A ratio of the secondlength L₂ to the first length L₁ is less than 2. In the illustratedembodiment, the first length L₁ is about 0.7 inches and the secondlength L₂ is about 1.3 inches such that the ratio of the second lengthL₂ to the first length L₁ is about 1.8. These relatively short inletpath lengths L₁, L₂ help reduce the pressure drop within the secondarycyclone stage.

As shown in FIGS. 4 and 5, the air outlets 118 of the cyclones 90, 94are defined by the inlet tubes 82 of the upper body portion 50. Theillustrated inlet tubes 82 extend partially into each of the cyclones90, 94. A cover plate 134 is positioned between the cyclone unit 34 andthe upper body portion 50 to help support the upper body portion 50 onthe cyclone unit 34. The cover plate 134 defines openings 138 (FIG. 2)through which the inlet tubes 82 can extend into the cyclones 90, 94.

The particle outlets 122 of the cyclones 90, 94 are located at lowerends of the cyclones 90, 94 opposite from the air outlets 118. Theparticle outlets 122 direct dirt, dust, and other debris into the innerdirt cup 30. Each cyclone 90, 94 defines a longitudinal axis 142, 146extending between the air outlet 118 to the particle outlet 122. Asshown in FIG. 5, the particle outlets 122 of the first cyclones 90 arepositioned radially inward of the air outlets 118 such that thelongitudinal axes 142 are obliquely angled relative to the centrallongitudinal axis 58 of the body 26. As shown in FIG. 4, the particleoutlets 122 of the second cyclones 94 are aligned with the air outlets118 such that the longitudinal axes 146 are parallel to the centrallongitudinal axis 58 of the body 26.

As shown in FIG. 3, each cyclone 90, 94 has a maximum outer diameter D₁measured at the upper surface 110 of the cyclone unit 34. In someembodiments, the maximum outer diameter D₁ of each cyclone 90, 94 isbetween about 1.0 inch and about 1.5 inches. In the illustratedembodiment, the maximum outer diameter D₁ is about 1.2 inches. Eachcyclone 90, 94 thereby has a cross-sectional area, measuredperpendicular to the corresponding longitudinal axis 142, 146 of theindividual cyclone 90, 94, between about 0.8 square-inches and about 1.8square-inches. In the illustrated embodiment, the cross-sectional areaof each cyclone 90, 94 is about 1.1 square-inches. In other embodiments,the first cyclones 90 may have different maximum diameters andcross-sectional areas compared to the second cyclones 94.

In some embodiments, the upper surface 110 of the cyclone unit 34 may benon-planar. For example, the upper surface 110 may be spherical, convex,or otherwise rounded such that at least some of the cyclones 90, 94 aretilted or obliquely angled relative to the central longitudinal axis 58of the body 26. In such embodiments, the maximum diameters D₁ andcross-sectional areas of the cyclones 90, 94 may be measured throughdifferent planes relative to each other.

The illustrated cyclones 90, 94 are arranged along two circles 150, 154.The first cyclones 90 are arranged along the outer circle 150 adjacentthe outer perimeter 98 of the cyclone unit 34. The second cyclones 94are arranged along the inner circle 154 adjacent a central portion ofthe cyclone unit 34. As used herein, a “circle” refers to an imaginarycircle that extends through the centers of the corresponding cyclones90, 94, similar to a bolt circle. Each circle 150, 154 has its center ororigin defined by the central longitudinal axis 58 of the body 26. Thecircles 150, 154 have different diameters such that the first cyclones90 are spaced radially further from the central longitudinal axis 58than the second cyclones 94. For example, in the illustrated embodiment,the first, or outer, circle 150 has a diameter D₂ of about 4.4 inches,while the second, or inner, circle 154 has a diameter D₃ of about 2.6inches. In other embodiments, the diameters D₂, D₃ of the circles 150,154 may be relatively larger or smaller.

In the illustrated embodiment, each second cyclone 94 is nested betweentwo adjacent first cyclones 90. That is, a portion of each secondcyclone 94 is positioned radially further from the central longitudinalaxis 58 of the body 26 than portions of the two adjacent first cyclones90 such that a radially-outermost point of the second cyclone 94 iscloser to the outer perimeter 98 of the cyclone unit 34 thanradially-innermost points of the two adjacent first cyclones 90. Withsuch an arrangement, a radial distance R between the outer circle 150and the inner circle 154 (e.g., about 0.9 inches) is less than themaximum diameters D₁ of the cyclones (e.g., about 1.2 inches).

In addition, the number of first cyclones 90 is substantially equal tothe number of second cyclones 94. “Substantially equal” means the numberof first cyclones 90 is within one of the number of second cyclones 94.For example, in the illustrated embodiment, the plurality of firstcyclones 90 includes six cyclones, and the plurality of second cyclones94 includes six cyclones. In other embodiments, the plurality of firstcyclones 90 may include one more or one fewer cyclone than the pluralityof second cyclones 94, yet the number of cyclones in each plurality maystill be substantially equal. Because each cyclone 90, 94 is associatedwith one inlet path 126, 130, the number of first inlet paths 126 isalso substantially equal to the number of second inlet paths 130. Assuch, the number of first cyclones 90, the number of first inlet paths126, the number of second cyclones 94, and the number of second inletpaths 130 are all substantially equal. In other embodiments, the numberof first cyclones 90 and/or inlet paths 126 may not be substantiallyequal to the number of second cyclones 94 and/or inlet paths 130.

Furthermore, the first and second cyclones 90, 94 alternate around thecentral longitudinal axis 58 of the body 26. Similarly, the first inletpaths 126 and the second inlet paths 130 alternate around the centrallongitudinal axis 58. Each second inlet path 130 thereby extends fromthe inlet space 106 to one of the second cyclones 94 between twoadjacent first cyclones 90. In addition, each inlet path 126, 130 has anend 158, 162 at the outer perimeter 98 of the cyclone unit 34 incommunication with the inlet space 106. The ends 158 of the first inletpaths 126 are circumferentially spaced evenly about the outer perimeter98. The ends 162 of the second inlet paths 130 are alsocircumferentially spaced evenly about the outer perimeter 98. The ends158, 162 of the first and second inlet paths 126, 130 alternate aroundthe outer perimeter 98 such that airflow circling around the inlet space106 passes a first inlet path end 158, then a second inlet path end 162,then a first inlet path end 158, and so on. Such an arrangement makesthe cyclone unit 34 generally symmetrical about the central longitudinalaxis 58.

The outer perimeter 98 of the cyclone unit 34 defines a total diameterD₄ and a total cross-sectional area of the cyclone unit 34. The totalcross-sectional area is measured perpendicular to the centrallongitudinal axis 58 of the body 26 at the upper surface 110 of thecyclone unit 34. This is also the cross-section of the cyclone unit 34at which the diameters of the cyclones 90, 94 are equal to the maximumdiameter D₁. The total cross-sectional area represents a footprint areaof the cyclone unit 34, which ignores the fact that some material isremoved from the cyclone unit 34 to form the cyclones 90, 94. In someembodiments, the total diameter D₄ of the cyclone unit 34 is betweenabout 5.5 inches and about 6.0 inches, and the total cross-sectionalarea of the cyclone unit 34 is between about 23 square-inches and about29 square-inches. In the illustrated embodiment, the total diameter D₄is about 5.8 inches, and the total cross-sectional area is about 26.5square-inches.

As noted above, each of the illustrated cyclones 90, 94 has across-sectional area, measured perpendicular to the central longitudinalaxis 58, of about 1.1 square-inches. Since there are twelve cyclones 90,94 in the illustrated embodiment, a sum of the cross-sectional areas ofthe first and second cyclones 90, 94 is about 13.2 square-inches. Assuch, a ratio of the sum of the cross-sectional areas of the cyclones90, 94 to the total cross-sectional area of the cyclone unit 34 is about0.5. In other embodiments, the ratio may be between about 0.4 and about0.6. The first and second cyclones 90, 94 are thereby designed andarranged to utilize a relatively large amount of the cross-sectionalarea of the cyclone unit 34. The amount of unused or ‘dead’ space withinthe cyclone unit 34 is thereby reduced.

The inner surface 102 of the mid body portion 46 defines a diameter D₅that is greater than the total diameter D₄ of the cyclone unit 34 todefine the inlet space 106. In some embodiments, the diameter D₅ of themid body portion 46 is between about 6.5 inches and about 7.0 inches. Inthe illustrated embodiment, the diameter D₅ is about 6.8 inches. Assuch, a cross-sectional area of the inlet space 106, measuredperpendicular to the central longitudinal axis 58, is between about 4square-inches and about 15 square-inches. In the illustrated embodiment,the cross-sectional area of the inlet space 106 is about 9.8 squareinches. In some embodiments, a ratio of the sum of the cross-sectionalareas of the cyclones 90, 94 to the cross-sectional area of the inletspace 106 is between about 1.3 and about 1.5. Additionally oralternatively, a ratio of the total cross-sectional area D₄ of thecyclone body 34 to the cross-sectional area of the inlet space 106 isbetween about 2 and about 3.

As shown in FIGS. 2 and 4-5, the cover 38 is positioned on top of theupper body portion 50. In the illustrated embodiment, the cover 38includes a handle 166 to facilitate lifting and carrying the cyclonicseparator assembly 22 apart from the vacuum 10. In some embodiments, thehandle 166 may also be used to lift the vacuum 10 while the cyclonicseparator assembly 22 is connected to the vacuum 10. A filter 170 iscaptured between the cover 38 and the upper body portion 50. The filter170 filters fine particles out of the airflow exiting the cyclone unit34 before the airflow is discharged from the separator assembly 22.

In operation, airflow enters the cyclonic separator assembly 22 throughthe inlet 62 in the lower body portion 42. The airflow circles throughthe lower body portion 42 to separate relatively large debris from theairflow. The debris falls into the primary dirt cup 66 defined by thelower body portion 42. The partially-cleaned airflow then travelsthrough the perforated baffle 78 of the mid body portion 46 and into theinlet space 106 between the mid body portion 46 and the cyclone unit 34.Next, the airflow enters the inlet paths 126, 130 in the cyclone unit 34to flow into the first and second cyclones 90, 94. The airflow circleswithin the first and second cyclones 90, 94 to separate relatively smalldebris from the airflow. The debris falls out of the cyclones 90, 94 andinto the inner dirt cup 30. Then, the airflow travels out of thecyclones 90, 94 through the inlet tubes 82 in the upper body portion 50and toward the filter 170. As the airflow flows through the filter 170,the filter 170 removes fine debris from the airflow. After passingthrough the filter 170, the relatively clean airflow is discharged fromthe cyclonic separator assembly 22 through the outlet 86 in the upperbody portion 50. Upon leaving the cyclonic separator assembly 22, theair is passed down to a suction motor (not shown) in the bottom of thehandle 18, and then the air is exhausted from the suction motor into theatmosphere.

Various features and advantages of the invention are set forth in thefollowing claims.

1. A cyclonic separator assembly for use with a vacuum cleaner, thecyclonic separator assembly comprising: a body having an inlet, anoutlet, and a central longitudinal axis; and a cyclone unit positionedwithin the body between the inlet and the outlet, the cyclone unithaving an outer perimeter that defines a total cross-sectional area ofthe cyclone unit measured perpendicular to the central longitudinalaxis, the cyclone unit including a plurality of first cyclones arrangedalong an outer circle adjacent the outer perimeter, each first cyclonehaving an air outlet, a particle outlet, a first longitudinal axisextending between the air outlet and the particle outlet, and a firstcross-sectional area measured perpendicular to the first longitudinalaxis, and a plurality of second cyclones arranged along an inner circlethat is spaced apart from the outer circle, each second cyclone havingan air outlet, a particle outlet, a second longitudinal axis extendingbetween the air outlet and the particle outlet, and a secondcross-sectional area measured perpendicular to the second longitudinalaxis; wherein the plurality of first cyclones and the plurality ofsecond cyclones are arranged in parallel, and wherein a ratio of the sumof the first and second cross-sectional areas to the totalcross-sectional area is between about 0.4 and about 0.6.
 2. The cyclonicseparator assembly of claim 1, wherein the ratio is about 0.5.
 3. Thecyclonic separator assembly of claim 1, wherein each first cyclone has afirst maximum diameter and each second cyclone has a second maximumdiameter, and wherein the first maximum diameter is generally equal tothe second maximum diameter.
 4. The cyclonic separator assembly of claim3, wherein the first maximum diameter and the second maximum diameterare about 1.2 inches.
 5. The cyclonic separator assembly of claim 1,wherein the body includes an inner surface, wherein the outer perimeterof the cyclone unit is spaced apart from the inner surface to define andinlet space therebetween, and wherein the plurality of first cyclonesand the plurality of second cyclones are in communication with the inletspace.
 6. The cyclonic separator assembly of claim 5, wherein the inletspace has a cross-sectional area measured perpendicular to the centrallongitudinal axis, and wherein a ratio of the sum of the first andsecond cross-sectional areas to the cross-sectional area of the inletspace is between about 1.3 and about 1.5.
 7. The cyclonic separatorassembly of claim 1, wherein the plurality of first cyclones and theplurality of second cyclones alternate around the central longitudinalaxis.
 8. The cyclonic separator assembly of claim 7, wherein each secondcyclone is nested between two adjacent first cyclones.
 9. A cyclonicseparator assembly for use with a vacuum cleaner, the cyclonic separatorassembly comprising: a body having an inlet, an outlet, and an innersurface; and a cyclone unit positioned within the body between the inletand the outlet, the cyclone unit having an outer perimeter that isspaced apart from the inner surface of the body to define an inlet spacetherebetween, the cyclone unit including a plurality of first cyclonesarranged along an outer circle adjacent the outer perimeter, a pluralityof first inlet paths extending from the inlet space to the plurality offirst cyclones, each first inlet path having a first length, a pluralityof second cyclones arranged along an inner circle that is spaced apartfrom the outer circle, and a plurality of second inlet paths extendingfrom the inlet space to the plurality of second cyclones, each secondinlet path having a second length; wherein a ratio of the second lengthto the first length is less than
 2. 10. The cyclonic separator assemblyof claim 9, wherein the ratio of the second length to the first lengthis about 1.8.
 11. The cyclonic separator assembly of claim 9, whereinthe body defines a central longitudinal axis, and wherein the pluralityof first inlet paths and the plurality of second inlet paths alternatearound the central longitudinal axis.
 12. The cyclonic separatorassembly of claim 9, wherein each second inlet path extends from theinlet space to one of the plurality of second cyclones between twoadjacent primary cyclones.
 13. The cyclonic separator assembly of claim12, wherein each second cyclone is nested between two adjacent firstcyclones.
 14. The cyclonic separator assembly of claim 9, wherein thenumber of inlet paths in the plurality of first inlet paths issubstantially equal to the number of inlet paths in the plurality ofsecond inlet paths.
 15. The cyclonic separator assembly of claim 14,wherein the number of cyclones in the plurality of first cyclones issubstantially equal to the number of cyclones in the plurality of secondcyclones.
 16. The cyclonic separator assembly of claim 15, wherein thenumber of inlet paths in the plurality of first inlet paths issubstantially equal to the number of cyclones in the plurality of firstcyclones.
 17. The cyclonic separator assembly of claim 9, wherein eachfirst cyclone has a first maximum diameter and each second cyclone has asecond maximum diameter, and wherein the first maximum diameter isgenerally equal to the second maximum diameter.